/*

HTML Escaping code
Copyright (C) 2000 Marc Palmer / AnyWare Ltd.

Acording to Marc, this code may be used under any license.
Thanks to Jason Hunter for his great book "JAVA Servlet Programming" used as
the source for the entity mappings. Thanks to CARDIACS for making the
most joyful music (www.cardiacs.com/button.html)

http://www.anyware.co.uk/java for updates and other stuff

@author Marc Palmer
@author Marcel Huijkman

@version	15-07-2002
*/

package org.webmacro.util;

/**
 * This class will escape characters that have an HTML entity
 * representation. It will not escape standard ASCII characters unless
 * it is necessary (i.e. will not escape ASCI #32 but will escape "&amp;").
 * Any characters with no corresponding entity are passed through unchanged.
 * It uses a quick string -> array mapping to avoid creating thousands of
 * temporary objects.
 */
public class HTMLEscaper
{

    /**
     * This method will take the input and escape characters that have
     * an HTML entity representation.
     * It uses a quick string -> array mapping to avoid creating thousands of
     * temporary objects.
     * @param nonHTMLsrc String containing the text to make HTML-safe
     * @return String containing new copy of string with ENTITIES escaped
     */
    public static final String escape (String nonHTMLsrc)
    {
        if (nonHTMLsrc == null)
            return null;

        StringBuffer res = new StringBuffer();
        int l = nonHTMLsrc.length();
        int idx;
        char c;
        for (int i = 0; i < l; i++)
        {
            c = nonHTMLsrc.charAt(i);
            idx = entityMap.indexOf(c);
            if (idx == -1)
            {
                res.append(c);
            }
            else
            {
                res.append(quickEntities[idx]);
            }
        }
        return res.toString();
    }

    /**
     * These are probably HTML 3.2 level... as it looks like some HTML 4 entities
     * are not present.
     */
    private static final String[][] ENTITIES = {
        /* We probably don't want to filter regular ASCII chars so we leave them out */
        {"&", "amp"},
        {"<", "lt"},
        {">", "gt"},
        {"\"", "quot"},

        {"\u0083", "#131"},
        {"\u0084", "#132"},
        {"\u0085", "#133"},
        {"\u0086", "#134"},
        {"\u0087", "#135"},
        {"\u0089", "#137"},
        {"\u008A", "#138"},
        {"\u008B", "#139"},
        {"\u008C", "#140"},
        {"\u0091", "#145"},
        {"\u0092", "#146"},
        {"\u0093", "#147"},
        {"\u0094", "#148"},
        {"\u0095", "#149"},
        {"\u0096", "#150"},
        {"\u0097", "#151"},
        {"\u0099", "#153"},
        {"\u009A", "#154"},
        {"\u009B", "#155"},
        {"\u009C", "#156"},
        {"\u009F", "#159"},

        {"\u00A0", "nbsp"},
        {"\u00A1", "iexcl"},
        {"\u00A2", "cent"},
        {"\u00A3", "pound"},
        {"\u00A4", "curren"},
        {"\u00A5", "yen"},
        {"\u00A6", "brvbar"},
        {"\u00A7", "sect"},
        {"\u00A8", "uml"},
        {"\u00A9", "copy"},
        {"\u00AA", "ordf"},
        {"\u00AB", "laquo"},
        {"\u00AC", "not"},
        {"\u00AD", "shy"},
        {"\u00AE", "reg"},
        {"\u00AF", "macr"},
        {"\u00B0", "deg"},
        {"\u00B1", "plusmn"},
        {"\u00B2", "sup2"},
        {"\u00B3", "sup3"},

        {"\u00B4", "acute"},
        {"\u00B5", "micro"},
        {"\u00B6", "para"},
        {"\u00B7", "middot"},
        {"\u00B8", "cedil"},
        {"\u00B9", "sup1"},
        {"\u00BA", "ordm"},
        {"\u00BB", "raquo"},
        {"\u00BC", "frac14"},
        {"\u00BD", "frac12"},
        {"\u00BE", "frac34"},
        {"\u00BF", "iquest"},

        {"\u00C0", "Agrave"},
        {"\u00C1", "Aacute"},
        {"\u00C2", "Acirc"},
        {"\u00C3", "Atilde"},
        {"\u00C4", "Auml"},
        {"\u00C5", "Aring"},
        {"\u00C6", "AElig"},
        {"\u00C7", "Ccedil"},
        {"\u00C8", "Egrave"},
        {"\u00C9", "Eacute"},
        {"\u00CA", "Ecirc"},
        {"\u00CB", "Euml"},
        {"\u00CC", "Igrave"},
        {"\u00CD", "Iacute"},
        {"\u00CE", "Icirc"},
        {"\u00CF", "Iuml"},

        {"\u00D0", "ETH"},
        {"\u00D1", "Ntilde"},
        {"\u00D2", "Ograve"},
        {"\u00D3", "Oacute"},
        {"\u00D4", "Ocirc"},
        {"\u00D5", "Otilde"},
        {"\u00D6", "Ouml"},
        {"\u00D7", "times"},
        {"\u00D8", "Oslash"},
        {"\u00D9", "Ugrave"},
        {"\u00DA", "Uacute"},
        {"\u00DB", "Ucirc"},
        {"\u00DC", "Uuml"},
        {"\u00DD", "Yacute"},
        {"\u00DE", "THORN"},
        {"\u00DF", "szlig"},

        {"\u00E0", "agrave"},
        {"\u00E1", "aacute"},
        {"\u00E2", "acirc"},
        {"\u00E3", "atilde"},
        {"\u00E4", "auml"},
        {"\u00E5", "aring"},
        {"\u00E6", "aelig"},
        {"\u00E7", "ccedil"},
        {"\u00E8", "egrave"},
        {"\u00E9", "eacute"},
        {"\u00EA", "ecirc"},
        {"\u00EB", "euml"},
        {"\u00EC", "igrave"},
        {"\u00ED", "iacute"},
        {"\u00EE", "icirc"},
        {"\u00EF", "iuml"},

        {"\u00F0", "eth"},
        {"\u00F1", "ntilde"},
        {"\u00F2", "ograve"},
        {"\u00F3", "oacute"},
        {"\u00F4", "ocirc"},
        {"\u00F5", "otilde"},
        {"\u00F6", "ouml"},
        {"\u00F7", "divide"},
        {"\u00F8", "oslash"},
        {"\u00F9", "ugrave"},
        {"\u00FA", "uacute"},
        {"\u00FB", "ucirc"},
        {"\u00FC", "uuml"},
        {"\u00FD", "yacute"},
        {"\u00FE", "thorn"},
        {"\u00FF", "yuml"},
        {"\u0080", "euro"}
    };

    private static String entityMap;
    private static String[] quickEntities;

    static
    {
        // Initialize some local mappings to speed it all up
        int l = ENTITIES.length;
        StringBuffer temp = new StringBuffer();

        quickEntities = new String[l];
        for (int i = 0; i < l; i++)
        {
            temp.append(ENTITIES[i][0]);
            quickEntities[i] = "&" + ENTITIES[i][1] + ";";
        }
        entityMap = temp.toString();
    }
}
